Speed reduction mechanism



2 i m $351: j, g, UTTLE ETAL SPEED REDUCTION MECHANISM Filed Sept.

2 Sheets sheet l .J. BL/TTLE INVENTORS- W AJWNSON ATTORNEY J. B. LETTLEETAL.

SPEED REDUCTION MECHANISM 2 SheetsSheet Filed Sept. 20, 1944 .J.B.L/T7LEgf: WAMUNSON Patented Jan. 4, 1949 UNITED STATES PATENT OFFICE SPEEDREDUCTION MECHANISM John B. Little, Summit, and Wilden A. Munson,Chatham, N. J., assignors to Bell Telephone Laboratories, Incorporated,New York, N. Y., a corporation of New York Application September 20,1944, Serial No. 554,894

relative movement of the elements of one or a plurality of ball bearingsis utilized for frictionally driving a power take-01f shaft and a powertake-01f drum at different stages of speed reduction.

In ball bearings, as it is well known, rings are generally used forholding the balls in races formed in concentrically disposed rings, theball retaining rings being rotated by the planetary movement of theballs due to friction between these balls and the concentric rings at aspeed ratio depending upon the difference between the diameters of theball races in the concentric rings.

According to the construction of the speed reduction mechanism of thisinvention a drum member is provided for mounting ball bearings incoaxial relation to each other, while coupling elements are provided foroperatively connecting the successive ball holding rings of the bearingswith the successive inner race rings of these hearings, with provisionfor rotatably mounting the drum itself on supports secured to a base. Acover member for the drum serves to secure the outer rings of the ballbearings and spacer elements disposed therebetween against rotarymovement relative to each other in the drum, while means in the form ofkey ways in the openings of the inner disposed race rings of the ballbearings engage with means formed with the coupling elements which inturn may be engaged by means carried by a shaft movable longitudinallyfor operatively connecting the shaft with the inner race rings of thebearings selectively.

A locking element carried by a stationary support which is secured tothe base is provided for engaging with a complement locking elementcarried by the power take-oil drum to cause the rotary movement of thepower take-off shaft according to the selected speed reduction, while alock element carried by the power take-off shaft is provided forengaging with a complement lock element carried by the stationarysupport for locking the power take-off shaft against movement to causethe rotation of the power take-off drum when unlocked in a directionopposite to that imparted to the power take-ofi shaft but at a stage ofspeed reduction depending upon the bearing selected by the adjustingmovement of the power take-off shaft as indicated by a pointer carriedby the shaft movable in registry with numbers printed on a dial.

Other novel features and advantages of the invention will appear fromthe following descrip-' tion and by the claims appended theretoreference being had to the accompanying drawings in which:

Fig. 1 is a side elevational view shown with a number of operating partsin longitudinal vertical section;

Fig. 2 is a perspective view of one of the ball bearings and one of thecouplings, the ball bearing being shown with portions broken away;

Fig. 3 is a side view of a modification of Fig. 1 shown partly invertical section; and

Fig. 4 is a view similar to Fig. 1 showing a modification of thecoupling disposed between the ball retaining rings of the bearings andthe inner race rings of such bearings.

In the speed reduction mechanism of this invention as shown in Fig. 1, abase i0 is provided for mounting the upright supports ll, I2 and 13which are secured to the base by a number of similar screws [4. Theupright supports H and I 2 are fitted with ball bearings 15 and 16,respectively, serving for rotatably supporting a power take-off drumelement I! having a lock element in the form of a flange portion I8 atone end thereof provided with a plurality of similarly sized holes IQfor engagement by a cooperating lock element in the form of a thumbscrew '20 carried by a projection W formed with the upright support I3,for locking this power takeoff drum against rotary movement for causingthe rotation of a power take-ofi shaft as will be hereinafter describedin detail.

In the drum H as shown in Fig. 1 is mounted a series of ball bearingsBI, B2, B3, B4 and B5 which may be of any desired number held in spacedrelation to each other by washers as WH while the outer disposed racerings of ball bearings BI, B2, B3, etc. and the rings WI-I are heldcollectively against relative rotary movement in the drum by thetightening of a closure in the form of a plug 2| threadedly engaging theopen end of drum element H. The inner disposed race rings of ballbearings B2, B3, etc. are formed with parallelly disposed slots orkeyways 22 best seen in Fig. 2 for receiving the key portions 23 formedwith the cylindrical portion of coupling elements as CE, the keyportions 23 of each cou pling element CE in turn forming a keyway to beengaged by a key 24 carried by a power take-off shaft 25 manuallymovable longitudinally for operatively and selectively engaging with theinner race rings of ball bearings B2, B3, B4 and B5 as will behereinafter described in detail, the arms 26 of each coupling member CEbeing formed at their free ends with bent portions as 21 serving asbearing surfaces resting against the corrugations formed by theirrespective ball retaining rings 28. e

A driving shaft 294s journaled in a sleeve s held against frictionalmovement upon the rotation of this shaft by an arm a1" engaging a pin Platerally extending from support 12. .The shaft 29 is provided with akey 30 for operatively engaging a keyway in the inneriracering.;ofrballbearing Bi for rotating thisring upon ithexop'eration of a motor 32, thear-mature shaft-33 of which is connected to the shaft 29 by a couplingsleeve 34.

Support 13 as shown in Fig. 1 is provided with a lock element in theform of a disc portion 35, having a plurality OfnhOlGS 36 for individualengagement with allock element inithedorm of a thumb screw '3?lzthrieaded'ly engaging the free "end of an arm 38 which is heldagainstrotary movement :on "thezsh'aft 2 5 by a s'et screw "G l"engaging a keywaywtZ-so asiitoper'mi't rthe'longitudinal. movement of T'Dh'lS :shaft for: connection of the latter selectively relative to themner'irace rings of ball b83)IlllgS1'B2,: B3, IE4 and .B5, the arm 38being held inposition adjacent ithe disc upon the longitudinal movementof Ish'aft 2-25-4103 afork-shaped extension 24]! :of 7 support (I 3engaging with a collar 39-attheperiphery:of ai'hub formed with thearm'.;38.

FIII the speed "reduction-mechanism 'of ithis'invention as shown in Fig.l and'in its modification shown in Fig. 3'-fiye-bal-l bearings have beenchosen for reducing the speed =ofumotor132 {0116 third at each stageof-speed reductionism vfrom:2;99v-7 revolutions perrninute to 2999 for.the-first stage of speed reduction, 333-for the :second stage, llll forthe'third stageand 3'7 for the fourth-stage as impartedtopower take-01fshaft :25 when the thumb screws .28 and 3 7 are positionedas'indicatedin-Fig. 1, such speed reduction being :indicated-by an index in-the formof. aridge-R carried by shaft 25 in cooperation with marks ,printedon adial D secured to the fork shaped extension-40 of support #3 by aplurality ,of screws-SC.

The conditioning of the speed reduction {for operating the powertake-off drum l1 and the I dition the drum H is rotated onbeanings and16 in a direction opposite to that impartedto shaft. 25 in each stage ofspeedreduction which in connection withthe operation .of drum All thespeed of the motor32 isreduced in four. difierent stagesto 9.99, 333,111 and 3-7 at the ball :bearing B14 which due to thelocked condition ofshaft 25 now in engagement with the-tinnerirace wing of bearing B5preventsthe rotation of .ballretaining ring '23 of ball bearingvB landthereby theplanetary movement of the balls of thisbear'ing. Whilecausing the rotation of the outer disposed ,race ring of bearing 34 andthe consequent rotation of drum I? in a direction opposite to ,thatlimparted to shaft 25 ashabovetdescribed,

In the modification of the speed reduction mechanism of thisin-ven'tionas-shownJin Figs. 3 and 4 a mounting plate is proyidedifor secur- "ingas by a'number ofscrews X,la'.motor 5!, while a sleeve 53 is fittedin anopening the platje i5 0 4 in position concentric to the armature shaft52 of motor 5! and held securely thereon by a nut 54 and a shoulderportion SP formed with the sleeve. The sleeve 53 serves as a casing forhousing a plurality of ball bearings Yl, Y2, Y3 and Y4 held in spacedrelation to each other by rings TI, 12 and 13; while a coupling elementr55 =-;operatively ..conne'ctsf the ball retaining ring; of-ball bearingY! with the inner race ring of ball bearing Y2.

lit-Another coupling element 56 operatively connects the ball retainingring of ball bearing Y2 with the inner'race "ring of ball bearing Y3 anda third coupling element-5"l,-;operative1y connects the ball aixetainingring :ofvbearing 56 with the inner race ring 20f :ball bearing Y4 whilea fourth coupling element 58 operatively connects the ball retainingring ofballbearing Y4 with a ring 60 press-fitted into the opening oftheinner race ring of the ball bearing "Y5 housed in a cup-shaped ring 6|threadedly engaging aiscrew-threaded portion at wthewfree en'dofsleeve-ifl :as shownainr -l igxfip A nut 62 engages the cup-shapedring 62' for-forcing the outer'ring oftiballabeairing 1Y5 ,againstaperi- :phera-l ridge formed with a ring i63 inaturn abutting againstthe outer. race tringtof .ball bearing Y4 ;-for collectively holding thespacer. rings 07 #2 and Ti and .the outer race rings.-of.-.ball-bearings Y3, Y2 and Y! securely ,aga-inst movement inelative toeach other in the sleeve 53.

t On the sleeve 53 is mountedal-iball ibearing 54 having two --rows ofballsL and :LZ tsenving'Ior vrotatably mounting a s-hubimember 5secured-@130 the outer race (ring of this ball bearing bygainllt .rinJiG' while to onesend of hub ,65;is securedlas ;by a number of screws.68 .avcover elementafiil having a ridge 69formedathenewi-thsfittedawithta coupling ring 70 .engaging'zthe ballnetainingring of ball bearing Y5, thus cooperating withathe couplingelements 55 -56, 5L and- 58 tfiorsoperw ,tive'ly connecting theiarmatureishaft 52 toftmotor 5 l to .thehub on ball bearing 54.

The hub 65 islprovided with .a.flange ,portion 171 .having aperipherally: disposed ,shoulden :portion 12 fitted witheandnum r131secunelyl-lhcld-ion shoulder portionl'i2 .byiairing 14 having alshoulderportion forced against theaedge "of the drumtby the tightening of .ia..plurality of nuts fl'r5.-,-on.studs '76 laterallyextendingfromthefiangeofidrumfi5, drum "73 being frictionally rntated.atagspeed-of substantially '3'! turns'i'fforieach "2,9957 revolutions ofthe armature shaft or. motorJ-il In a typical exampleiofl operation .ofthe speed reduction mechanism shown, in Fig. l'the. rotation of armatureshaft 13.3 \of'mo'tor. 32 matlthe assumed rate of 2,997 turns, per,.minuteuiswlfiectiyieto rotate the s'haftfl'atand' therebylithe'innerirace ring of ball 'bea'ring'B'fl. "The,,,op.erationincl-the'innerflring of ball bearing Bil .jis impartedtoritsrespectively"associated lball retaining rin due to the planetary(movement ofitheiballs. that ring at aspeed ratio of 'one'turnfor eachthree turns ofinner race ring of ball bearing 31 or 999iturns '-f oreach 259'9Tturns 'oT themotorarmature shaft, while the rotation' o'f theba'll retai-ning ri-ng'rof ibearing'iB l isdmparted -'-to the innerrace*ring 'of ballbearing'BZ and to} its respectively associated ballretaining wring: ntaac speed three dimes less than {that of .sthe in'nermace ring of :the rl'atteniball :bearingaor 333 rturns peri -minute;LthBBQ'BQMBIIIED-t of the innern raceipirbalbibearingnBc directly.;ao-,tuating the power take-wofi'rshaftrfi iatitheuspeed indicated by indexRdn (re istry with the mark V333-Hprinted lonediaLD. 5 The longitudinalimovement otpshazft 25 enagement with the inner racering of.ballbearings B4 or B5 will rotate the shaft at a speed of 111 and 37revolutions for each 2,997 turns of motor shaft 33.

In this mechanism the disengagement of thumb screw 20 from the flange 18of power take-off drum l7 and the engagement of thumb screw 31 with oneof the holes 36 in disc 35 is effective to lock the shaft 25 and therebythe inner race ring of ball bearing B3 against rotation. The rotation ofshaft 29 as above described is effective to rotate the inner race ringof ball bearing BI and its ball retaining ring which in turn through itscoupling element CE rotates the inner ring of ball bearing B2. Theoperation of this ring and the consequent rotation of the balls of thisbearing, however, is ineffective to rotate their associated ballretaining ring due to the coupling element CE connecting with this ringbeing prevented from rotation by the shaft 25 which is now locked bythumb screw 31 as above described. Under this condition rotation of theinner ring of bearing B2 is effective to rotate the balls and therebyimparting rotation to the power take-off drum in a direction opposite tothe direction of movement imparted to the shaft 25 for each selectivemovement of shaft 25 relative to the successive ball bearings B2, B3, B4and B5.

In the operation of the modified speed reduction shown in Figs. 3 and 4the operation of motor 5| at a speed of 2,997 revolutions per minute,for example, is effective to rotate the inner race ring of bearing Y!which rotation is imparted to the ball retaining ring of this bearing ata reduced speed of 999 revolutions per minute and through the couplingelement 55 to the inner race ring of bearing Y2 which in turn impartsmovement to its associated ball retaining ring at the rate of 333 turnsper minute. The rotation of this ball retaining ring through coupling 56is effective to impart rotation to the ball retaining ring of thishearing at the rate of 111 turns for actuating its own ball retainingring at the rate of 37 turns per minute while through the couplingelement 58 rotation of the ball retaining ring of ball bearing Y4 iseffective to i rotate the ring 69 and thereby the inner race ring ofball bearing Y5 the rotation of which actuates the coupling ring at arate of 12+ revolutions per minute for rotating the drum 13 used, forexample, to drive the magnetic tape in a sound recording and reproducingmachine. Slipping at the last stage of speed reduction has been reducedto a minimum by the use of a ball bearing of a much greater diameterthan that used for the first, second and third stages of speedreduction.

What is claimed is:

1. In a speed reduction mechanism, a rotatable drum, a plurality ofpairs of concentrically disposed rings in said drum, a plurality ofballs disposed between said rings in each of said pairs, rings havingmeans for holding said balls in the annular spaces between saidconcentric rings, a plurality of coupling means for successivelyoperatively connecting the ball retaining rings of said bearings tosimilar successive rings in said pairs of concentric rings, a drivenshaft movable longitudinally for individually engaging said similarrings, a locking mechanism for holding said shaft from rotation to causethe movement of said drum in one direction, and a locking mechanism forlocking said drum to cause the operation of said shaft in anotherdirection upon the unlocking of the latter by the first-mentionedlocking mechanism.

2. In a speed reduction mechanism, a rotatable drum, a plurality ofpairs of concentrically disposed rings in said drum, a plurality ofballs disposed in the annular space between said rings in each of saidpairs, rings having means for holding said balls between said concentricrings, a plurality of coupling means for successively operativelyconnecting the ball retaining rings of said bearings to similarsuccessive rings in said pairs of concentric rings, a power take-offshaft movable longitudinally for successively engaging means carriedthereby with means in said similar rings, for rotation according to theengaged ring a manually operable locking mechanism for holding saidshaft from rotation to cause the rotating movement of said drum in onedirection at predetermined speeds, a locking mechanism for holding saiddrum from rotation to cause the operation of said shaft in a directionopposite to the direction of rotation of said drum following the manualoperation of the unlocking of said shaft by the first-mentioned lockingmechanism.

3. In a speed reduction mechanism a rotatable drum, a plurality of pairsof concentrically disposed rings in said drum, a plurality of ballsdisposed in the annular space between said rings in each of said pairs,rings having means for holding said balls in the annular spaces, aplurality of coupling means for successively operatively con necting theball retaining rings of said bearings to similar successive rings insaid pairs of concentric rings, a power take-off shaft movablelongitudinally for engaging means in said similar rings, a lockingmechanism for holding said shaft from rotation to cause the movement ofsaid drum in one direction at a predetermined speed, a mechanism forlocking said drum to cause the operation of said shaft in a directionopposite to said drum at another speed upon the unlocking of said shaftby the first-mentioned lock mechanism, a scale, means carried by saidshaft cooperating with said scale for indicating the successive speedsof said shaft, and another power takeoff shaft element carried by saiddrum.

JOHN B. LITTLE. WILDEN A. MUNSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,058,275 Torday Apr. 8, 19131,201,364 Shelton Oct. 17, 1916 1,201,367 Shelton Oct. 17, 19161,256,175 Shelton Feb. 12, 1918 1,986,177 Fastoupil Jan. 1, 1935 FOREIGNPATENTS Number Country Date 17,547 Great Britain Dec. 15, 1915

